Kapex 120 - inaccuracy with bevel cuts

[Blakkness]

Hi guys,

I'm experiencing some lack of accuracy with bevel cuts.

First of all, let me say that lasers are calibrated (what a PITA, but it's done!).
Miter angle is calibrated too, at least for 90° cuts, with an outstanding accuracy out-of-the-box of -0,046 °

Lets start with cross cuts at 90°, no problem at all : the pen line is parallel to the lasers.

From start ...

... to end.

But now, with a 45° bevel cut.

From start ...

... to end

With this 300mm wide piece of wood, there is an offset of almost 1mm. Thats huge !
Same case with à -45° bevel cut.

Do I have something else to calibrate ?

While reading the supplemental's user's manual, I can't find my case explained.

Any help will be highly appreciated

Blakk'

 

[NYC Tiny Shop]

You're best off contacting Festool USA on Monday morning and discuss this with Brent, Lester, or Clint in tech support.  They will help you with any concerns, problems, or issues that you have with any Festool product.

 

[tjbnwi]

You're best off contacting Festool USA on Monday morning and discuss this with Brent, Lester, or Clint in tech support.  They will help you with any concerns, problems, or issues that you have with any Festool product.

It may be an expensive phone call seeing as he is in France. Might have a language issue also.

Tom

 

[Blakkness]

You're both right.

I'll call Festool France tomorrow.

 

[Rick Christopherson]

What you are showing isn't all that bad considering how much weight is being cantilevered. With the saw fully beveled like that, the full weight of the motor is suspended sideways from the carriage. This will twist the carriage on any saw. The fact that it is twisting by about only the thickness of a pencil line is pretty impressive.

 

[Blakkness]

What you are showing isn't all that bad considering how much weight is being cantilevered. With the saw fully beveled like that, the full weight of the motor is suspended sideways from the carriage. This will twist the carriage on any saw. The fact that it is twisting by about only the thickness of a pencil line is pretty impressive.

I agree with you, it's not that bad ... but more than 1° offset.
With two bevel cuts by piece of wood, the offsets are added.
I make a sort of box, with ~2mm of difference between top and bottom for each side, I'm afraid of the result after joining the pieces together  [unsure]
A sort of pyramid, actually  [big grin]

The Kapex is very expensive, so I'm very demanding.

 

[Rick Christopherson]

I agree with you, it's not that bad ... but more than 1° offset.

Based on estimating distances from your photographs, I'd put the error to be less than 0.1 degrees, not greater than a full degree as you suggested. Even if I go larger than it appears and choose 0.030" over 10 inches, it is still only 0.17 degrees. You'll get greater variability than that simply by how your hand biases the carriage during the cut.

It's not a matter of cost. There is no such thing as a perfectly rigid assembly. Even my old Northfield Unipoint would flex when the carriage is cantilevered to the side. It will always be present any time you have an over-arm saw with a zero-point entry. Conversely, my Craftsman Industrial RAS won't deflect during a bevel because the motor tilts but remains below the carriage. However, that is not a zero-point entry.

 

[Deansocial]

Less than 1/5 of a degree.

 

[glass1]

Actually it's not that bad only a thin pencil line at best. That's not the complaint. It's lined up when the saw is not beveled but out when the saw is beveled. And no the saw head is fully retracted and not fully extended causing weight on the bars, furthermore it's about the inconsistency it I understand the op.

 

[Deansocial]

In fact looking at the gap between the lasers assuming a 2.5mm blade set at 45° the gap would be 3.53mm so the offset would be less than 1mm maybe 0.6 0.7mm making it closer to 1/10 of a degree.

 

[Brice Burrell]

I'm with Rick on this one, it's just the nature of miter saws.  They are made to be portable and have numerous moving parts, there's no way they can produce truly "perfect" cuts.  For some perspective, grab another brand miter saw and see what you get...

 

[ScotF]

I agree with you, it's not that bad ... but more than 1° offset.

Based on estimating distances from your photographs, I'd put the error to be less than 0.1 degrees, not greater than a full degree as you suggested. Even if I go larger than it appears and choose 0.030" over 10 inches, it is still only 0.17 degrees. You'll get greater variability than that simply by how your hand biases the carriage during the cut.

It's not a matter of cost. There is no such thing as a perfectly rigid assembly. Even my old Northfield Unipoint would flex when the carriage is cantilevered to the side. It will always be present any time you have an over-arm saw with a zero-point entry. Conversely, my Craftsman Industrial RAS won't deflect during a bevel because the motor tilts but remains below the carriage. However, that is not a zero-point entry.

I am still in awe that Rick as a Northfield Unipoint...what an awesome machine. 

Scot

 

[Blakkness]

I agree with you, it's not that bad ... but more than 1° offset.

Based on estimating distances from your photographs, I'd put the error to be less than 0.1 degrees, not greater than a full degree as you suggested. Even if I go larger than it appears and choose 0.030" over 10 inches, it is still only 0.17 degrees. You'll get greater variability than that simply by how your hand biases the carriage during the cut.

It's not a matter of cost. There is no such thing as a perfectly rigid assembly. Even my old Northfield Unipoint would flex when the carriage is cantilevered to the side. It will always be present any time you have an over-arm saw with a zero-point entry. Conversely, my Craftsman Industrial RAS won't deflect during a bevel because the motor tilts but remains below the carriage. However, that is not a zero-point entry.

Well, my apologies ...
I re-done the math, and it's 0,19° (tan-1(1/300)) for a 1mm offset, not 1°. Shame on me.

Two more shots, left and right. Between 1 and 2 mm offset. So, 0,19°

 

[Blakkness]

Actually it's not that bad only a thin pencil line at best. That's not the complaint. It's lined up when the saw is not beveled but out when the saw is beveled. And no the saw head is fully retracted and not fully extended causing weight on the bars, furthermore it's about the inconsistency it I understand the op.

You're absolutely right.

It's all about inconsistency, depending on the angle of bevel.
Another disturbing thing, with bevel, the cut isn't between the lasers. But stays parallel to the lasers.

 

[Blakkness]

I'm with Rick on this one, it's just the nature of miter saws.  They are made to be portable and have numerous moving parts, there's no way they can produce truly "perfect" cuts.  For some perspective, grab another brand miter saw and see what you get...

It's against my religion : Festool for life  [big grin]

 

[Rick Christopherson]

I am still in awe that Rick as a Northfield Unipoint...what an awesome machine.  

Scot

You're right. It is a totally awesome machine. However, it was too big, even for my shop. I sold it after restoring it. I bought it at an auction for $600 because there weren't supposed to be any power tools there, so the only person bidding against me was Amish and was going to pull the motor and run it from a line shaft.  [scared]

Here is an interesting aside though. Two months ago I visited my old high school woodshop for my son's 9th grade orientation. The new shop teacher (small engines, woods, drafting, graphic arts) is the son of my old shop teacher (small engines, electronics, drafting, but not woods). The wood shop wasn't part of the open-house, but the teacher gave me and my son a private tour.

I was shocked to discover that the shop is fully intact and virtually unchanged after all these years. Within 1 second of stepping through the doors, my eyes fixated on the big radial arm saw still sitting in the exact same location. OMG!!! After all these years, I had never realized it had been a Northfield Unipoint all along!!!

The teacher told me that the school board had once tried to get rid of the saw because it was missing a screw on the blade guard.  [scared] Instead of replacing a $0.20 screw, they were going to dump a $15,000 saw!! Thankfully the teacher prevailed and the saw was repaired.

I was so impressed with how complete the woodshop remains after all these years, I got Festool's permission to donate one of the extra TS55REQ saws in my possession to the school. (They don't have any guided saws, but do teach cabinetry classes.) I just need to figure out how to get them a guide rail, because I don't have any spares myself.

 

[ajones]

I am still in awe that Rick as a Northfield Unipoint...what an awesome machine.  

Scot

You're right. It is a totally awesome machine. However, it was too big, even for my shop. I sold it after restoring it. I bought it at an auction for $600 because there weren't supposed to be any power tools there, so the only person bidding against me was Amish and was going to pull the motor and run it from a line shaft.  [scared]

Here is an interesting aside though. Two months ago I visited my old high school woodshop for my son's 9th grade orientation. The new shop teacher (small engines, woods, drafting, graphic arts) is the son of my old shop teacher (small engines, electronics, drafting, but not woods). The wood shop wasn't part of the open-house, but the teacher gave me and my son a private tour.

I was shocked to discover that the shop is fully intact and virtually unchanged after all these years. Within 1 second of stepping through the doors, my eyes fixated on the big radial arm saw still sitting in the exact same location. OMG!!! After all these years, I had never realized it had been a Northfield Unipoint all along!!!

The teacher told me that the school board had once tried to get rid of the saw because it was missing a screw on the blade guard.  [scared] Instead of replacing a $0.20 screw, they were going to dump a $15,000 saw!! Thankfully the teacher prevailed and the saw was repaired.

I was so impressed with how complete the woodshop remains after all these years, I got Festool's permission to donate one of the extra TS55REQ saws in my possession to the school. (They don't have any guided saws, but do teach cabinetry classes.) I just need to figure out how to get them a guide rail, because I don't have any spares myself.

I could see Shane stepping up and supplying a guide rail if he was asked [poke]

 

[nclemmons]

I agree with you, it's not that bad ... but more than 1° offset.

Based on estimating distances from your photographs, I'd put the error to be less than 0.1 degrees, not greater than a full degree as you suggested. Even if I go larger than it appears and choose 0.030" over 10 inches, it is still only 0.17 degrees. You'll get greater variability than that simply by how your hand biases the carriage during the cut.

It's not a matter of cost. There is no such thing as a perfectly rigid assembly. Even my old Northfield Unipoint would flex when the carriage is cantilevered to the side. It will always be present any time you have an over-arm saw with a zero-point entry. Conversely, my Craftsman Industrial RAS won't deflect during a bevel because the motor tilts but remains below the carriage. However, that is not a zero-point entry.

I am still in awe that Rick as a Northfield Unipoint...what an awesome machine. 

Scot

I'm in awe that it can cut that accurately and the table has no cut in it!

 

[Rick Christopherson]

I could see Shane stepping up and supplying a guide rail if he was asked [poke]

Technically they are already donating the saw, so I have been hesitant to ask. I already know that if I ask Michael Williams, one or more would be sent without the slightest hesitation. I've been hoping to find a local dealer that had a slightly marred rail that they can't otherwise sell.

 

[Rick Christopherson]

I'm in awe that it can cut that accurately and the table has no cut in it!

That's because I put a brand new top on it to sell it, and didn't want to make any cuts before it was sold. It's not a factory top, though.

The previous owner was Pella Windows, and they had the coolest dual miter fence installed. It could simultaneously miter both left and right miters, but the blade remained at 90 degrees. This saw was also upgraded to the 18 inch blade package.